Can you add food coloring to glass etching cream?

You could -- but for what purpose? It does not colour the glass but etches or eats away the surface layer of the glass. The cream is made up of a mixture of acids, which dissolve some of the glass. The colour would serve no purpose at all. It would be washed off and would just be a waste of product. If you wanted to get some colour on the etched areas, you would have to do it in two steps: etch first, and then add colour after. But food colouring alone would not stick to the etched surface; it would wash off quickly. You would need some sort of paint, but one that would not leave a smooth shiny finish. It may be best to just leave the etched surface as it is.

Colored Etching Cream

No it does not tried it this morning and it just etched the glass no color guess we need to use color glass for that

Could try using permanent markers after the etching is done. I would try it before removing the stencil but after you have washed the etching cream off. I haven't tried this, so I don't know if it would work.